Refrigerating apparatus



March 26, 1963 M. K. TUCKER 3,082,937

REFRIGERATING APPARATUS Filed Nov. 725, 1960 2 Sheets-Sheet 1 mmvroze. w "mar/an 7216/0? BY i I ms ATTORMEY March 26, 1963 M. K. TUCKER 3,082,937

REFRIGERATING APPARATUS Filed Nov. 25, 1960 2 Sheets-Sheet 2 IN VEN TOR.

mar/an A. 7216A?! H25 ATTORN Y United States 3,082,937 REFRIGERATING APPARATU Marion K. Tucker, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich.,'a corporation of Delaware Filed Nov. 25, 1960, Ser. No. 71,524

2 Claims. (Cl. 230207) This invention relates to refrigerating apparatus and more particularly to a low side rotary compressor.

One of the major problems in designing a rotary compressor for use in the refrigerating system wherein the compressor housing is maintained at low pressure is that of providing adequate lubrication for the shaft bearings. The reason for this is that in conventional rotary compressors the high pressure gas within the compression chamber tends to leak past the end surface of the impeller and past the shaft bearings so as to wipe these urfaces clean of lubrication which is needed for proper lubrication of these surfaces.

It is an object of this invention to provide an improved oiling arrangement which eliminate this problem.

More particularly, it is an object of this invention to provide the end surface of the impeller with a circumferentially extending groove which is vented to the low pressure side of the system once during each revolution of the compressor.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a vertical sectional view taken substantially on line 11 of FIGURE 2.

FIGURE 2 is a plan view of the compressor with parts broken away showing various details of construction.

Referring now to the drawings wherein a preferred embodiment of the invention has been shown, reference numeral designates an inverted cup-shaped sheet metal casing element which serves to enclose the motor compressor assembly, generally designated by the reference numeral 12. The motor compressor assembly includes a cast frame element 14 which is resiliently supported within the casing 10 in any suitable manner, such as by means of coil springs 16 supported on a compressor mounting ring member 17 which is held in place in the lower part of the casing 10 by means of the housing end plate member 18. The member 18 is welded or otherwise secured to the casing element 10.

A motor stator 20 is supported on the frame element 14 and a complementary motor rotor 22 is supported on the upper end of the main compressor drive shaft 24. The drive shaft 24 is provided with an eccentric portion 26 which cooperates with a refrigerant impeller ring 28 disposed in the compression chamber 30. The chamber 30 is formed between the lower surface of the casting 14 and the upper surface of a lower end plate element 32. The main cylinder portion 34 is held in place between the frame element 14 and the end plate 32 by means of mounting bolts 36 in accordance with conventional practice.

A divider blade 40 is slidably supported in a slot formed in the cylinder element 34 and is arranged to have its inner end slidably engage the outer periphery of the im-' peller 28. The gas to be compressed enters the compression chamber through an inlet 42 and leaves the compression chamber through an outlet 44. Gas to'be compressed enters the upperportion of the casing 10 through the. suction line 46 whereby the relatively cold incominggas is required to pass in thermal exchange relationship with the motor stator 20 on its way to the compressor inlet 42. The compressed gas leaves through an outlet line 48.

The lower portion of the housing 10 serves as a lubricant reservoir from whence oil for lubricating the shaft bearings is withdrawn by means of an oil pump having an inlet 50 communicating with the oil in the lower portion of the casing 10'. For purposes of illustration, the oil pump has been shown as being a multiple vane type pump mounted on the lower end of the drive shaft 24. The oil pump is arranged to discharge a portion of the oil handled by the pump into an axial passage 52 provided in the drive shaft 24 and also directs a portion of the oil into a passage 54 which feeds lubricant into a groove 56 provided in the lower end surface of the impeller 28 intermediate the inner and outer edges of the impeller. The'impeller is provided with axially extending passages 58 which feed a portion of the lubricant from the groove 56 into a corresponding groove 60' formed in the upper surface of the impeller ring 28. A vent passage 62 is formed in the casting 14 for communicating with the groove 60 once during each revolution of the shaft 24. The oil feed passage 54 is arranged to supply oil to the grooves 56 and 60 during the first degrees of the compression stroke and the vent 62 is open during the last 180 degrees of the compression stroke. By virtue of this construction, it is apparent that the high pressure gas which might tend to escape from the compression chamber past the ends of the impeller ring 28 will be vented to the low pressure side of the system through the passage 62 when the compression pressure is high with the result that there will be no appreciable tendency for the escaping high pressure gas to try to escape past the main shaft bearing surface 70.

The oil passage 52 formed in the shaft 24 communicates with a plurality of radially extending oil feed passages 72 which feed lubricant to the main shaft bearing surfaces. The upper end of the oil passage 52 is provided with a ball type check valve 74 which only opens when the pressure at the outlet of the oil pump exceeds the pressure required for properly lubricating all of the bearing surfaces.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to, be understood that other forms might be adopted.

What is claimed is as follows:

1. In a rotary compressor, a frame element, a shaft journaled in said frame element, means cooperating with said frame element to form a rotary compression chamber, inlet and outlet ports for said chamber, said shaft having an eccentric portion thereon, an impeller on said eccentric portion arranged to operate in said compression chamber to compress gas therein, said impellercomprising a ringlike element, a circumferentially extending groove formed in each end surface of said ring-like element intermediate the inner and outer edges thereof, passage means connecting said grooves, means for supply- 3 irig Iu'bricaritunde'r pressure to said grooves and to said passage means, and means for equalizing the pressure within said groove with the pressure at said inlet port during the final portion of the compression stroke, said last named means comprising a vent port arranged to be covered by one end portion of said impeller during the beginning of the compression stroke and to be uncovered during the final portion of said compression stroke.

2. In a rotary compressor, a frame element having a shaft bearing formed therein, a shaft journaled in said bearing, means cooperating with said frame element to form a compression chamber, said shaft having an eccentricportion thereon, an impeller on said eccentric portion arranged to operate in'said compression chamber, an oil pump drivingly connected tosaid shaft for supplying oil to the compressor bearing surfaces and having an outcircumferentially extending groove formedin one end of said ririg-likeelement intermediate the inner and outer edges thereof and arranged to move into and out of alignment Withfsaid outlet port for supplying lubricant from said pump to said groove during the first portion only of the compression stroke of said impeller, and means for equalizing the pressure within said groove with the pressure at the inlet of said compressor during another portion of the compression stroke of said impeller.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain Nov. 3, 1938 

1. IN A ROTARY COMPRESSOR, A FRAME ELEMENT, A SHAFT JOURNALED IN SAID FRAME ELEMENT, MEANS COOPERATING WITH SAID FRAME ELEMENT TO FORM A ROTARY COMPRESSION CHAMBER, INLET AND OUTLET PORTS FOR SAID CHAMBER, SAID SHAFT HAVING AN ECCENTRIC PORTION THEREON, AN IMPELLER ON SAID ECCENTRIC PORTION ARRANGED TO OPERATE IN SAID COMPRESSION CHAMBER TO COMPRESS GAS THEREIN, SAID IMPELLER COMPRISING A RINGLIKE ELEMENT, A CIRCUMFERENTIALLY EXTENDING GROOVE FORMED IN EACH END SURFACE OF SAID RING-LIKE ELEMENT INTERMEDIATE THE INNER AND OUTER EDGES THEREOF, 